JP2003005383A - Resist stripper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an excellent resist remover not containing hydroxylamine having a high explosion hazard and a resist remover having titanium oxide removing performance. SOLUTION: A resist remover which comprises a peroxide and a quaternary ammonium salt is prepared and used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stripping agent for stripping a photoresist layer and titanium oxide in the manufacturing process of semiconductor integrated circuits, printed wiring boards, liquid crystals and the like.

[0002]

2. Description of the Related Art In a semiconductor integrated circuit, a substrate is coated with photo resist, exposed and developed, and then etched to form a circuit, and then a photoresist is peeled from the substrate or after the circuit is formed. After ashing to remove the resist, the remaining resist residue is peeled off. Conventionally, various resist stripping agents have been proposed for stripping the photoresist from the substrate or stripping the resist residue from the substrate. JP 62-49
Japanese Patent No. 355 discloses a resist stripping composition using alkanolamines. However, the stripping solution composition using an alkanolamine is insufficient for stripping a resist residue that has undergone a treatment such as dry etching, ashing, or ion implantation and has been transformed into an inorganic property. In addition, with the latest submicron processing technology, TiN,
Metallic materials including TiSi and the like are used, but when these metallic materials are used, stable by-products such as titanium oxide are generated during processing. Titanium oxide could not be stripped with the previously used alkanolamines.

Therefore, recently, a resist stripping composition having a more excellent stripping property has been proposed which contains hydroxylamine. For example, JP-A-4-289866 discloses a resist stripping solution composition containing hydroxylamine and alkanolamine.
Japanese Patent Laid-Open Publication 9 proposes a resist stripping composition containing hydroxylamine, alkanolamine and catechol. Although the resist stripping composition containing hydroxylamine exhibits excellent titanium oxide stripping properties, it is an unstable compound and therefore there is a risk of decomposition and explosion.

In addition to the basic amine-based resist stripping agent as described above, a resist stripping agent in which hydrogen peroxide and an acid are combined has been proposed (Japanese Patent Laid-Open No. 64-15740). It is generally known that titanium oxide dissolves in hydrogen peroxide under acidic conditions, but it can be said that the combination of hydrogen peroxide and acid is the most suitable for stripping a basic and easy-to-peel alkaline developing photoresist. There wasn't.

[0005]

As described above, the conventionally proposed resist strippers have insufficient strippability, particularly titanium oxide strippability, and there is a risk of decomposition and explosion. Therefore, an object of the present invention is to provide a resist stripper that does not contain hydroxylamine, which has a high risk of explosion, and that exhibits excellent resist strippability and titanium oxide strippability.

[0006]

Means for Solving the Problems As a result of intensive investigations by the present inventors, a resist stripper composed of a peroxide and a quaternary ammonium salt has been found to have improved resist strippability and titanium oxide strippability. They have found that they can be used as excellent resist strippers, and have completed the present invention.

That is, the present invention is a resist stripper comprising a peroxide and a quaternary ammonium salt.

The present invention will be described in detail below.

In the present invention, peeling means removing a residual resist or a resist residue after applying a photoresist on a substrate, exposing, developing, etching, etc. to form a circuit. . That is, the development exposes the photoresist and removes the resist solubilized in the liquid, and removes the portion left by the development, or the portion that becomes difficult to dissolve in the liquid after processing such as etching and ashing. Is peeling.

The resist stripper of the present invention is used for stripping photoresist or its residue. That is, after coating the photoresist on the substrate, exposing and developing,
After a circuit is formed by performing a treatment such as etching, the resist is stripped with the resist stripping agent of the present invention. Alternatively, after circuit formation, ashing is performed to remove the resist, and the remaining resist residue is removed with the resist remover of the present invention.

The resist stripping agent of the present invention strips not only the resist but also titanium oxide which is a by-product of circuit formation. Among the titanium oxides, particularly tetravalent titanium oxides are extremely stable compounds and are hardly soluble in water. There are various valences of titanium oxide, such as tetravalent, trivalent, and divalent, but the most difficult one is tetravalent titanium oxide (titanium dioxide). On the other hand, the most soluble titanium species is Ti ²⁺ , and it is known that titanium oxide in the solid phase is easily dissolved by reducing in the acidic region. However, the resist remover of the present invention can reduce and dissolve various titanium oxides including titanium dioxide, which is the most difficult to dissolve in the alkaline region where the resist can be removed, and can be removed.

The essential components of the resist stripper of the present invention are a peroxide and a quaternary ammonium salt.

The peroxide used in the resist stripper of the present invention acts as a reducing agent.

The peroxide used in the resist stripper of the present invention is selected from the group consisting of hydrogen peroxide, persulfates, perborates, percarbonates, organic peracids, and organic hydroperoxides. Is at least one. Of these, hydrogen peroxide is the cheapest and is industrially preferable. Hydrogen peroxide is anhydrous or aqueous solution, as well as hydrogen peroxide such as urea or quaternary ammonium salt (like hydrogen in crystal water, hydrogen peroxide is coordinated to urea or quaternary ammonium salt) Can also be used. Inorganic persalts such as persulfates, perborates and percarbonates are preferably used as salts with ammonia, amines or quaternary ammonium salts. Other salts, such as sodium salt and potassium salt, can be used, but they require removal of metal ions and are not industrially advantageous. The organic peracid is not particularly limited as long as it is stable even when mixed with a quaternary ammonium salt, but by way of example, formic acid, peracetic acid, benzoyl peroxide, m-chloroperbenzoic acid, etc. may be mentioned. Can be mentioned. Organic hydroperoxide has the general formula R-OOH.
(R represents alkyl, aryl, etc.), and exemplarily includes butyl hydroperoxide,
Examples include cumyl hydroperoxide and the like.

As the quaternary ammonium salt that can be used in the resist remover of the present invention, any quaternary ammonium salt can be used as long as it exhibits alkalinity. Examples of the quaternary ammonium salt include at least one selected from the group consisting of quaternary ammonium hydroxide, quaternary ammonium carbonate, quaternary ammonium carboxylate, and quaternary ammonium peroxycarboxylate. Can be mentioned. All of these are alkaline substances, and they may be used alone or in a mixture. Among these quaternary ammonium salts, hydroxides and carboxylates are particularly preferable. As the carboxylic acid, any of an aliphatic carboxylic acid and an aromatic carboxylic acid can be used.As the aromatic carboxylic acid, for example, benzoic acid, salicylic acid, phthalic acid and the like can be mentioned, and as the aliphatic carboxylic acid, Examples include acetic acid, lactic acid, adipic acid, and propionic acid. Among them, aromatic carboxylic acids have good stability and are preferably used industrially.

The cation moiety in the quaternary ammonium salt used in the resist stripper of the present invention, that is, the quaternary ammonium, is tetramethylammonium,
Tetraalkylammonium such as tetraethylammonium, tetra-n-propylammonium, triethylmethylammonium, dodecyltrimethylammonium, benzyltrialkylammonium such as benzyltrimethylammonium, alkyl-hydroxylalkylammonium such as trimethyl-2-hydroxyethylammonium (choline) Is mentioned.

The resist stripper of the present invention may contain at least one selected from the group consisting of amines, water-soluble organic solvents, and water, in addition to peroxides and quaternary ammonium salts. As the amines that can be added to the resist remover, amines generally used as a resist remover may be added. Specifically, monoethanolamine, diethanolamine, triethanolamine, 2- (2-aminoethoxy) ethanol, N-
(2-Aminoethyl) ethanolamine, N, N-dimethylethanolamine, N, N-diethylethanolamine, N, N-dibutylethanolamine, N-methylethanolamine, N-ethylethanolamine, N-
Alkanolamines such as butylethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, N- (2-hydroxyethyl) piperazine, N- (2-hydroxyethyl) morpholine , Ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, piperazine,
Ethyleneamines such as N- (2-aminoethyl) piperazine and triethylenediamine, N, N, N ', N'-
Tetramethylethylenediamine, N, N, N ',
N ", N" -pentamethyldiethylenetriamine,
N-Methylpiperazine, N-alkylethyleneamines such as N, N, N′-trimethylaminoethylpiperazine, propanediamine other than ethyleneamine, butanediamine, diamines such as hexamethylenediamine, imidazole, 1-methylimidazole, 2-methylimidazole, 1,2-dimethylimidazole, 1,2,
4,5-Tetramethylimidazole, 2-ethyl-4-
Examples thereof include imidazoles such as methylimidazole, monoamines such as morpholine, cyclohexylamine, 2-ethyl-hexylamine, benzylamine and aniline, and alkylamines such as triethylamine, tripropylamine and tributylamine. Also, corrosion,
Hydroxylamines can also be added, although this is not preferred in view of risk. These amines may be used alone or in combination of two or more.

As the water-soluble organic solvent used in the present invention,
What is generally used as a resist stripping agent can be used. Examples of the water-soluble organic solvent include sulfoxides such as dimethyl sulfoxide, sulfones such as dimethyl sulfone and diethyl sulfone, N, N-dimethylformamide, N, N-diethylformamide,
Amides such as N, N-dimethylacetamide, N, N-diethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-propyl-2-
Lactams such as pyrrolidone and N-hydroxyethyl-2-pyrrolidone, imidazolidinones such as 1,3-dimezyl-2-imidazolidinone, ethylene glycol,
Glycols such as diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether,
Diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether,
Examples thereof include glycol ethers such as propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, and dipropylene glycol monobutyl ether. These water-soluble organic solvents may be used alone,
You may use it in mixture of 2 or more types.

A commonly used anticorrosive agent can be added to the resist remover of the present invention. As anticorrosives, formic acid, acetic acid, propionic acid, octylic acid, adipic acid, pimelic acid, sebacic acid, suberic acid, azelaic acid, benzoic acid, salicylic acid, carboxylic acids such as phthalic acid, nitrilotriacetic acid, ethylenediaminetetraacetic acid, diethylenetriamine Aminopolycarboxylic acids such as pentaacetic acid,
Examples thereof include aromatic hydroxyl group-containing compounds such as phenol, resorcinol, pyrocatechol and pyrogallol, azoles such as pyrrole, imidazole, triazole and tetrazole, and sugars such as glucose, sucrose and fructose.

In the resist stripper of the present invention, it is difficult to limit the ratio of peroxide, quaternary ammonium salt, water, amines, and water-soluble organic solvent, because the ratio varies depending on the compound used. However, the peroxide is 0.1 to 30% by weight, and the quaternary ammonium salt is 1 to 50%.
% By weight, 1 to 90% by weight of water, 1 to 50% by weight of amines, and 1 to 50% by weight of water-soluble organic solvent. Preferably, 0.5 to 25% by weight of peroxide, 5 to 50% by weight of quaternary ammonium salt, 1 to 90% by weight of water, 1 to 40% by weight of amines, and 1% of water-soluble organic solvent. ~ 50% by weight. More preferably, the peroxide is 1 to 25% by weight,
Quaternary ammonium salt 5 to 40% by weight, water 1 to 90
% By weight, 1 to 30% by weight of amines, and 1 to 50% by weight of water-soluble organic solvent. Even if it deviates from this range, it cannot be used, but the releasability and stability of the resist are deteriorated.

The resist stripper of the present invention may be used by adding each component when stripping the resist, or may be used after mixing each component in advance.

The quaternary ammonium salt and the peroxide used in the resist stripper of the present invention may be present in the form of a simple mixture, or like the hydrogenated quaternary ammonium salt. The quaternary ammonium salt may be present in a form in which a peroxide is coordinated. When the peroxide is coordinated to the quaternary ammonium salt, the reaction of the peroxide and the additive and the reaction of the quaternary ammonium salt and the additive are suppressed when another is added to the resist stripping agent of the present invention. The range of substances that can be added is widened.

The resist remover of the present invention can be used for a resist which can be developed with an aqueous alkaline solution.

The resist stripping agent of the present invention is a photoresist film coated on an inorganic substrate, a photoresist layer remaining on a photoresist film coated on an inorganic substrate after dry etching, or ashing after dry etching. It is used for stripping the remaining photoresist residue and the like, and for stripping by-products such as titanium oxide. At that time, the stripping may be promoted by heating, ultrasonic waves or the like.

A dipping method is generally used as the method of using the resist stripping agent of the present invention, but other methods may be used.

[0026]

EXAMPLES The present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the invention thereto. Example 1-Example 27, Comparative Example 1-Comparative Example 8 A commercially available positive photoresist 2 was formed on a silicon wafer.
It was applied in a thickness of μm and prebaked. Then, it was exposed through a mask pattern and developed with tetramethylammonium hydroxide. After etching, plasma ashing treatment was performed. This silicon wafer is shown in Table 1.
It was immersed in the stripping solution shown in 80 ° C. for 30 minutes, then washed with water and dried. The surface was observed by a scanning electron microscope to examine the peelability of the resist-altered film and the titanium oxide.

The corrosiveness of the metal was evaluated by immersing the test piece of each metal (copper, aluminum) in the resist stripping agent shown in Table 2 at 50 ° C. for 30 minutes, changing the weight and observing the surface.

The stripping solutions of the examples were prepared by adding peroxide to an aqueous quaternary ammonium salt solution at 30 ° C. to remove excess water, and then adding amines and a water-soluble organic solvent. . In the case of hydrogen peroxide, 35% hydrogen peroxide solution was used, and the hydrogen peroxide solution was added to the quaternary ammonium salt aqueous solution at 80 ° C. The compositions are shown in Tables 1 and 2, with the balance being water. <Resist strippability and titanium oxide strippability> The strippability of the resist-altered film and the strippability of titanium oxide were evaluated as follows.

◯: Good releasability Δ: Some residue remained ×: Most remained <Corrosion of metal> Corrosion to copper and aluminum was evaluated as follows (however, for hydroxylamine, It could not be tested because it decomposes when it comes into contact with copper).

◯: No corrosion Δ: Partially corroded ×: Severe corrosion In addition, the following abbreviations are used to simplify the description in Tables 1 and 2.

TMAH: Tetramethylammonium hydroxide TEAH: Tetraethylammonium hydroxide TPAH: Tetra-n-propylammonium hydroxide TMHEAH: Trimethyl-2-hydroxyethylammonium hydroxide TMAC: Tetramethylammonium carbonate TPAC: Tetra-n-carbonate Propyl ammonium TMHEAC: Trimethyl-2-hydroxyethyl ammonium carbonate BTMAC: Benzyl trimethyl ammonium ammonium carbonate TMAA: Tetramethylammonium acetate TMAAP: Tetramethylammonium peracetate TMAS: Tetramethylammonium salicylate TMAB: Tetramethylammonium benzoate TMAL: Tetramethylammonium lactate TPAP: tetra-n-propyl propionate Ammonium BTMAA: Benzyltrimethylammonium adipate MEA: Monoethanolamine HA: Hydroxylamine TETA: Triethylenetetramine HPO: Hydrogen peroxide APS: Ammonium persulfate MBHEA: Methylbis (2-hydroxyethyl) cocomonium APB: Ammonium perborate APC: Ammonium Percarbonate BPO: Benzoyl Peroxide TBHPO: Tertiary Butyl Hydroperoxide NMP: N-Methyl-2-pyrrolidone DMSO: Dimethyl Sulfoxide

[0032]

[Table 1]

[Table 2]

INDUSTRIAL APPLICABILITY The resist stripping agent of the present invention does not contain unstable and highly dangerous hydroxylamine and can be used as a resist stripping agent exhibiting excellent resist stripping property and titanium oxide stripping property.

   ─────────────────────────────────────────────────── ─── Continued front page    (31) Priority claim number Japanese Patent Application No. 2001-123252 (P2001-123252) (32) Priority date April 20, 2001 (April 20, 2001) (33) Priority claiming country Japan (JP)

Claims (10)

[Claims] 1. A resist stripper comprising a peroxide and a quaternary ammonium salt. 2. The quaternary ammonium salt is selected from the group consisting of quaternary ammonium hydroxide, quaternary ammonium carbonate, quaternary ammonium carboxylate, and quaternary ammonium peroxycarboxylate. It is at least 1 type, The resist stripping agent of Claim 1 characterized by the above-mentioned. 3. The resist stripper according to claim 2, wherein the carboxylic acid in the quaternary ammonium carboxylate is an aromatic carboxylic acid. 4. The carboxylic acid in the quaternary ammonium carboxylate is at least one selected from the group consisting of benzoic acid, salicylic acid, and phthalic acid, and claim 2 or claim 3 characterized in that Resist stripping agent. 5. The quaternary ammonium in the quaternary ammonium salt is at least one selected from the group consisting of tetraalkylammonium, benzyltrialkylammonium, and alkyl-hydroxyalkylammonium. ~ The resist stripping agent according to claim 4. 6. The peroxide is at least one selected from the group consisting of hydrogen peroxide, persulfates, perborates, percarbonates, organic peracids, and organic hydroperoxides. The resist stripper according to any one of claims 1 to 5. 7. The peroxide and the quaternary ammonium salt are added with at least one selected from the group consisting of amines, a water-soluble organic solvent, and water.
~ The resist stripping agent according to claim 6. 8. The water-soluble organic solvent comprises sulfoxides, sulfones, amides, lactams, imidazolidinones,
The resist stripper according to any one of claims 1 to 7, which is at least one selected from the group consisting of glycols and glycol ethers. 9. The resist stripping agent according to claim 1, which strips titanium oxide. 10. The resist stripping agent according to claim 1, wherein after the photoresist is developed to form a circuit, the remaining resist or resist residue is stripped off.